1. Field of the Invention
The present invention relates to a dynamic absorber that extends from an actuator arm for a hard disk drive.
2. Background Information
Hard disk drives contain a plurality of heads that are each coupled to a surface of a rotating disk. Hard disk drives typically contain a number of disks that are assembled to a single spindle motor. Each head may contain a write element for magnetizing the disk surface and a read element for sensing the magnetic field of the disk surface to store and retrieve binary information as is well known in the art.
Each head is typically gimbal mounted to a suspension arm which is attached to an actuator beam of an actuator arm. The arms suspend the heads adjacent to the surfaces of the disks. The heads each have air bearing surfaces which cooperate with an air flow generated by the rotating disks to create an air bearing between the head and the disk surface. The air bearing minimizes the contact and mechanical wear between the head and the disk. It is desirable to provide an air bearing that is large enough to minimize mechanical wear while being small enough to optimize the magnetic coupling between the head and the disk surface. A head and suspension arm are commonly referred to as a head gimbal assembly (HGA).
The data is typically stored within a plurality of annular tracks that extend radially across a disk surface. Each track may contain a plurality of sectors that each contain a block of data along with servo bits and other information required to operate the drive. The actuator arm has a voice coil that is coupled to a magnet assembly of the disk drive. The voice coil and magnet assembly are commonly referred to as a voice coil motor (VCM). The voice coil motor can be excited to create a torque that swings the actuator arm and moves the heads across the surfaces of the disks. Movement of the actuator arm allows the heads to access the different tracks of the disks. Rotation of the disks allows the heads to access the different sectors of the tracks.
Disk drives can be subjected to shock loads which create a resonant displacement of the heads relative to the disk surfaces. The resonant displacement may create an error in writing or reading data. FIGS. 1 and 2 show the shock load and the lateral displacement at the end of an actuator beam, respectively, for a disk drive of the prior art. The lateral displacement is in a plane that is essentially parallel with the surface of the disk. As shown in FIG. 2, the shock load creates resonant displacement which moves the head relative to the disk. This movement may create an error in writing or reading data.
It is desirable to provide an actuator assembly that will dampen the shock load and minimize the amount of resonant displacement of the heads. There have been developed actuator arms which include a layer of damping material located on each surface of the actuator beams. This design does not sufficiently dampen shock loads transmitted into the actuator arm. It would be desirable to provide an actuator arm that dampens a shock load applied to the arm more effectively than designs of the prior art. It would also be desirable to provide such an actuator arm without significantly increasing the cost of constructing the arm.
One embodiment of the present invention is an actuator beam that can be incorporated into an actuator arm assembly of a hard disk drive. The actuator beam may include a dynamic absorber that extends from a distal end of the beam. The dynamic absorber may attenuate any resonant displacement in the actuator beam induced by a shock load that is applied to the hard disk drive.